1. Field of the Invention
This invention relates to an apparatus for measuring whether or not a machined part, immediately after being cut appropriately has been machined according to specifications.
2. Description of the Prior Art
In the present world where a remarkable improvement of productivity is required, a machining center plays an increasingly important role.
In view of this, products that have been machined are measured by a worker using a measuring apparatus (a measuring instrument or a gauge) at the machining site or in an inspection room (measurement and gauging) equipped with measuring apparatuses.
With this measuring system, considerable labor is required for the measuring work and the measurement cannot be known instantly immediately after the machining.
For this reason, the measurement cannot be corrected immediately at a machining center. Therefore, the effect of using the machining center is reduced considerably.
A sampling method is used for the measuring work which is especially burdensome.
In that case, all the articles machined after an article that has developed a trouble are assumed to be defective and require considerable labor for remachining, resulting in a considerably increased cost.
Also, a female screw has thus far been machined with a tool called a tap and therefore developed no variations in the machined size.
Recently, however, a method has been employed in which a planet tap is rotated (autorotation) for arcuate cutting (revolution) during which the work is fed by the pitch of the screw for threading.
According to this method, screws of different diameters can be machined with a single planet tap by changing the radius of revolution.
In this machining method, the size of the planet tap is measured, and the radius of revolution is calculated by subtracting the tap size from the machined diameter. The result is varied in size due to calculation errors or depending on the machining conditions. Thus the measuring work is required.
The measuring work, however, requires many gauges (go gauges and not--go gauges) conforming with the screw size and thread pitch.